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Journal of Wuhan University of technology(Materials science) 2024年第5期39卷 1319-1324页

作者： GAO Ying LIU Di WANG Aiyang ZHANG Song HE Qianglong REN Shifeng FANG Jie WANG Zihan WANG Weimin State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Jingdezhen Huaxun Special Ceramics Co.ltd. Jingdezhen 333000China aerospace science&industry defense technology research and test center Beijing 100854China

Micrometer-sized diamonds were incorporated into silicon nitride(Si_(3)N_(4))matrix to manufacture high-performance Si_(3)N_(4)-based composites using spark plasma sintering at 1500℃under 50 *** effects of the diamond content on the phase composition,microstructure,mechanical properties and thermal conductivity of the composites were *** results showed that the addition of diamond could effectively improve the hardness of the *** thermal conductivity of Si_(3)N_(4)increased to 52.97 W/m·k at the maximum with the addition of 15 wt%diamond,which was 27.5%higher than that of the monolithic Si_(3)N_(4).At this point,the fracture toughness was 7.54 MPa·m^(1/2).Due to the addition of diamond,the composite material generated a new substance,MgSiN2,which effectively combined Si_(3)N_(4)with ***2 might improve the hardness and thermal conductivity of the materials.

关键词： spark plasma sintering Si_(3)N_(4) diamond thermal conductivity mechanical properties

Fast solution to the free return orbit's reachable domain of the manned lunar mission by deep neural network

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Journal of Systems Engineering and Electronics 2024年第2期35卷 495-508页

作者： YANG Luyi LI Haiyang ZHANG Jin ZHU Yuehe College of aerospace science and Engineering National University of Defense TechnologyChangsha 410073China China Astronauts research and Training center Beijing 100094China Hunan Key Laboratory of Intelligent Planning and Simulation for aerospace Missions Changsha 410073China

It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight types of free return orbits and then the RD is defined by the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify neural network and a regression network are trained respectively. The former is built for classifying the type of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority in computation efficiency compared with the traditional double two-body model.

关键词： manned lunar mission free return orbit reachable domain(RD) deep neural network computation efficiency

Multi-Channel Based on Attention Network for Infrared Small Target Detection

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Journal of Shanghai Jiaotong university(science) 2024年第3期29卷 414-427页

作者：张彦军王碧云蔡云泽 Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of aerospace Control technology Shanghai 201109China Infrared Detection technology R&D center of China aerospace science and technology Corporation Shanghai 201109China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering research center of Intelligent Control and Management Shanghai 200240China Key Laboratory of Marine Intelligent Equipment and System of Ministry of Education Shanghai Jiao Tong UniversityShanghai 200240China Institute of Marine Equipment Shanghai Jiao Tong UniversityShanghai 200240China

Infrared detection technology has the advantages of all-weather detection and good concealment,which is widely used in long-distance target detection and tracking ***,the complex background,the strong noise,and the characteristics of small scale and weak intensity of targets bring great difficulties to the detection of infrared small targets.A multi-channel based on attention network is proposed in this paper,aimed at the problem of high missed detection rate and false alarm rate of traditional algorithms and the problem of large model,high complexity and poor detection performance of deep learning ***,given the difficulty in extracting the features of infrared multiscale and small dim targets,the multiple channels are designed based on dilated convolution to capture multiscale target ***,the coordinate attention block is incorporated in each channel to suppress background clutters adaptively and enhance target *** addition,the fusion of shallow detail features and deep abstract semantic features is realized by synthesizing the contextual attention fusion ***,it is verified that,compared with other state-of-the-art methods based on the datasets SIRST and MDFA,the proposed algorithm further improves the detection effect,and the model size and computational complexity are smaller.

关键词： infrared image small target detection deep learning attention mechanism feature fusion

AWK-TIS:An Improved AK-IS Based on Whale Optimization Algorithm and Truncated Importance Sampling for Reliability Analysis

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Computer Modeling in Engineering & sciences 2023年第5期135卷 1457-1480页

作者： Qiang Qin Xiaolei Cao Shengpeng Zhang aerospace science and industry Corporation defense technology research and test center Beijing100854China Key Laboratory for Thermal science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing100084China

In this work,an improved active kriging method based on the AK-IS and truncated importance sampling(TIS)method is proposed to efficiently evaluate structural *** novel method called AWK-TIS is inspired by AK-IS and RBF-GA previously published in the *** innovation of the AWK-TIS is that TIS is adopted to lessen the sample pool size significantly,and the whale optimization algorithm(WOA)is employed to acquire the optimal Krigingmodel and themost probable point(MPP).To verify the performance of theAWK-TISmethod for structural reliability,four numerical cases which are utilized as benchmarks in literature and one real engineering problem about a jet van manipulate mechanism are *** results indicate the accuracy and efficiency of the proposed method.

关键词： Structural reliability active kriging whale optimization algorithm AK-IS

A Review on the Precise Control of the Liquid Nitrogen Supplying System in Transonic Cryogenic Wind Tunnel

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Journal of Thermal science 2023年第2期32卷 692-707页

作者： ZHANG Wei GAO Rong CHENG Jun CHEN Wanhua SONG Yuanjia LIAO Daxiong College of aerospace science and Engineering National University of Defense TechnologyChangsha 410073China China Aerodynamics research and Development center Mianyang 621000China

The liquid nitrogen(LN2)supplying system,one of the four key systems of the cryogenic wind tunnel(CWT),is an essential guarantee for the precise control,fast and safe regulation of the wind tunnel’s total ***,the technical schemes,advantages and disadvantages of different LN2 supplying systems are discussed and analyzed based on the operation conditions and test requirements of different ***,together with the development of the pilot cryogenic transonic wind tunnel(PCTW),the key technologies of the system,including the supplying mode,rapid and accurate regulation of injection pressure,development of large scale cryogenic centrifugal pump,and matching technology between pumps and pipe network,have been summarized and the solutions to the existing issues are ***,a supplying process suitable for large-scale CWT is proposed,which has the ability of independent commissioning,rapid regulation,accurate control of injection pressure and transient response to the wind tunnel’s wide range of working *** breakthrough in LN2 supplying system enables China to construct a CWT for the future competitive high Reynolds number aircraft.

关键词： cryogenic wind tunnel liquid nitrogen supplying system working principle injection pressure dynamic simulation

Numerical simulation research on multiphase flow of aviation centrifugal pump based on OpenFOAM

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Chinese Journal of Aeronautics 2024年第4期37卷 256-275页

作者： Xianwei LIU Jiangfeng FU Junjie YANG Dewen YIN Zhenhua ZHOU Huacong LI College of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China Norinco Group testing and research Institute Huayin 714200China AECC Xi’an Engine Control technology Co.Ltd. Xi’an 710077China AECC Guizhou Honglin Aero Engine Control technology Co.Ltd. Guiyang 550009China

This paper aims to tackle the calculation efficiency problem raised in the cavitation-flow simulation of the aviation centrifugal pump due to the fading-away interface resulting from the dissipation of numerics used in the phase-change control equation for unstructured-grid multiphase flow,and due to the limitation of flow time-step in whole flow regimes,the control equation of vapor–liquid two-phase flow considering cavitation mass transport is established firstly,modifying the momentum equation by introducing the surface tension,and adding the artificial convective flow to the phase equation to solve the numerical dissipation ***,in consideration of the local time step principle and based on the multi-dimensional general limiter algorithm with explicit solutions under the OpenFOAM platform,a solution method of steady-state VOF (Volume of Fluid) model considering cavitation two-phase change is constructed,and the feasibility of this method is verified by NACA hydrofoil and NASA flat plate ***,based on the platform developed,the cavitation performance of an aviation centrifugal pump inducer is *** research results show that the error of the calculated cavitation pressure distribution for NACA hydrofoil between the simulation test and the experimental-test is less than 5%,and the maximum error of calculated cavitation number at pump head dropping for NASA high-speed flat plate inducer between the simulation test and the experimental-test is 2.1%.The cavitation area observed in the simulation test is the same as that obtained in the high-speed photography *** on the OpenFOAM simulation method,the position of pump head dropping of the fuel centrifugal pump can be accurately *** error of the calculated cavitation number at pump head dropping between the simulation test and the experimental test is about 3.7%,showing high calculation accuracy.

关键词： Aero engine Fuel centrifugal pump Multiphase flow OpenFOAM Volume of fluid

Shock wave and bubble characteristics of underwater array explosion of charges

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Defence technology（防务技术） 2022年第8期18卷 1445-1453页

作者： Hong-Wei Hu Pu Song Shuang-feng Guo Hai-yun Feng Dao-kui Li College of aerospace science and Engineering National University of Defense TechnologyChangsha410073HunanChina Xi'an Modern Chemistry research Institute Xi'an710065ShaanxiChina Hunan Key Laboratory of Intelligent Planning and Simulation for aerospace Missions Changsha410073HunanChina

In this study, we focused on the effect of the underwater explosion parameters of multi-point array explosion. The shock wave and bubble parameters of aggregate charge, two charges, and four charges were measured through an underwater explosion test, and their influence on the explosion power field of charge quantity and array distance was analyzed. Results show that the multi-shock wave collision of array explosion can be approximated to a linear superposition, and the interaction of delayed shock wave can be deemed as the increase of the shock wave baseline. Shock wave focusing and delayed superposition increase the shock wave peak pressure. Compared with the aggregate charge, the greater the number of array explosion points is, the higher the impulse and the gain of the bubble peak pressure are. At the same array distance, the smaller the charge quantity is, the higher the bubble impulse will be. At the same charge quantity, the smaller the array distance is, the higher the bubble impulse will be. The bubble period decreases gradually with the increase of the charge quantity, but the test orientation has little effect on the bubble period.

关键词： Explosion mechanics Underwater explosion Array explosion Shock waveBubble

Structural reliability analysis using enhanced cuckoo search algorithm and artificial neural network

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1317-1326页

作者： QIN Qiang FENG Yunwen LI Feng aerospace science and industry Corporation defense technology research and test center Beijing 100854China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China CASIC Space Engineering Development Co. LtdBeijing 100854China

The present study proposed an enhanced cuckoo search(ECS) algorithm combined with artificial neural network(ANN) as the surrogate model to solve structural reliability problems. In order to enhance the accuracy and convergence rate of the original cuckoo search(CS) algorithm, the main parameters namely, abandon probability of worst nests paand search step sizeα0 are dynamically adjusted via nonlinear control equations. In addition, a global-best guided equation incorporating the information of global best nest is introduced to the ECS to enhance its exploitation. Then, the proposed ECS is linked to the well-trained ANN model for structural reliability analysis. The computational capability of the proposed algorithm is validated using five typical structural reliability problems and an engineering application. The comparison results show the efficiency and accuracy of the proposed algorithm.

关键词： structural reliability enhanced cuckoo search(ECS) artificial neural network(ANN) cuckoo search(CS) algorithm

Influence of different rolling processes on microstructure and strength of the Al–Cu–Li alloy AA2195

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Progress in Natural science:Materials International 2022年第1期32卷 87-95页

作者： Fan Ye Ling Mao Jian Rong Baoshuai Zhang Lijun Wei Sihan Wen Haojun Jiao Sujun Wu International research center for Advanced Structural and Biomaterials School of Materials Science and Engineering Beihang University School of Materials science and Engineering Beihang University aerospace research Institute of Materials & Processing technology

The influence of different rolling processes on precipitation behaviour, crystallography texture, grain morphology,and their consequent effects on tensile properties for Al–Cu–Li alloy AA2195 was investigated in the present *** H-T8 samples(hot rolled + T8) presented better tensile strength and ductility(with serious strength anisotropy) than the HC-T8 samples(hot rolled + cold rolled + T8), due to their different microstructures and textures. The higher dislocation density was found in the H-T8 samples, which promoted the nucleation of main strengthening phase T1in the matrix and suppressed the grain boundary precipitation, resulted in better strength and ductility. The increase of the dynamic recovery(DRV) during hot rolling enhanced the generation of Brass texture, and brought serious strength anisotropy. The cold rolling was performed after the hot-rolling process for the HC-T8 samples which increased deformation energy and resulted in full recrystallization of the deformed microstructure during the following solution treatment. The formation of recrystallized microstructure reduced the dislocation density and the heterogeneous precipitate nucleation positions which limited the strengthening phase precipitation in matrix and accelerated the precipitation along grain boundaries, resulted in fewer T1precipitates, coarse grain-boundary precipitates(GBPs), and wider precipitate-free zones(PFZs). The localized strain may be concentrated on the grain boundary to induce the dislocation pile-up, breaking of the GBPs, and intergranular fracture during stretching.

关键词： Al-Cu-Li alloys Rolling Mechanical properties Microstructure evolution Fracture

Residual lifetime prediction model of nonlinear accelerated degradation data with measurement error

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Journal of Systems Engineering and Electronics 2017年第5期28卷 1028-1038页

作者： Zhongyi Cai Yunxiang Chen Qiang Zhang Huachun Xiang Equipment Management & Safety Engineering College Air Force Engineering University defense technology research Academy China Aerospace Science & Industry Corporation

For the product degradation process with random effect (RE), measurement error (ME) and nonlinearity in step-stress accelerated degradation test (SSADT), the nonlinear Wiener based degradation model with RE and ME is built. An analytical approximation to the probability density function (PDF) of the product's lifetime is derived in a closed form. The process and data of SSADT are analyzed to obtain the relation model of the observed data under each accelerated stress. The likelihood function for the population-based observed data is constructed. The population-based model parameters and its random coefficient prior values are estimated. According to the newly observed data of the target product in SSADT, an analytical approximation to the PDF of its residual lifetime (RL) is derived in accordance with its individual degradation characteristics. The parameter updating method based on Bayesian inference is applied to obtain the posterior value of random coefficient of the RL model. A numerical example by simulation is analyzed to verify the accuracy and advantage of the proposed model.

关键词： accelerated degradation test residual lifetime (RL) prediction measurement error random effect nonlinearity